command line - Forward SSH traffic through a middle machine

SSH tunneling is very confusing to me. I am wondering if I can do this in Linux.

I have 3 machines..

A. My local machine at home.
B. Machine at work that I can SSH into (middle man).
C. My desktop at work that I can only SSH into from machine B.

So I can SSH from A -> B and from B -> C, but not from A -> C.

Is there a way to setup an SSH tunnel from A through B, so when I run other SSH commands it they just work from my local machine A? I am basically trying to clone a git repo from work to home (and I cannot install git on machine B).

Also, once setup.. How would I unset it as well?